2018 F150 Lariat 4x4 5.0 with 10 speed. 105k miles. I bought it about ten months and 16k miles ago.

Symptom summary:
Blind spot system fault
Cross traffic system fault
Memory recall notice
Airbag lights come on
Outside temp indicator drops to 50
A/C turns off and won’t come back on
Radio controls won’t respond (but the steering wheel buttons work)
Power windows don’t work
Auto start/stop disable button won’t work, but truck doesn’t turn off when stopped
Key fob is not detected, then is, then isn't again

As you can see I’ve got a lot of weird stuff going on. It started two days ago on a two hour drive. The first thing was the blind spot and cross traffic system faults immediately followed by “memory recall not permitted while driving” even though I wasn’t trying to recall it. Then my A/C shut off and the outside temperature reading went to 50 even though it was probably 70 at the time. The lights for the A/C and the radio ***** also went out, and the airbag light on the dash came on, as well as the passenger airbag light under the center display.

This would cycle off and on throughout the drive. Oh and my power windows won't go down. The rear windows will, but not the front ones.

I immediately thought it might be the battery or alternator, but two different auto parts stores said both were good.

Then I read on here about water in the taillights causing the blind spot and cross traffic issues. I checked and realized I had a hole in the right lens and the bottom half was full of water (we had a couple of inches of rain the night before all this started). Since the light already had a hole in it, I drilled a very small hole in the bottom to drain the water out. I thought this would help but it hasn't.

The water might explain the issue with the two system faults, but what about all the other stuff going on?

The second day (yesterday) was worse, with the A/C turning off and never coming back on. It wouldn’t be so bad if I could roll down my windows. Then the truck stopped detecting the key while driving. I had to put the key in the cup holder slot to get the truck to recognize it. This morning when I went out to open the door the fob was recognized and the door unlocked when I touched the handle.

I don’t know what to do except take it to the dealer but the two closest to me are one week and three weeks out. Thanks for any suggestions.

 

How old is the battery? Have it load tested and charge state.

 

@garrech

take the taillight out, unplug it, and check the connector for any corrosion

while it is unplugged, turn the truck back on and see if any of the alerts go away (the BLIS and CTA will stay for obvious reasons). I have seen corroded wires / blis modules cause all kinds of communication network issues and i feel that is the root cause of all this. you have a bad module / corrosion dragging a network down (in this case the MS-CAN) which would explain a LOT of your issues. They are all tied in with the MS-CAN

 

The battery is dated 9/22, so less than two years old. I had it load tested at O'Reilly's and Advance Auto and both said it was good. Is that enough or is it still suspicious?

 

Thanks, I will try that tonight. I didn't drive it to work today (drove the '08 with 350k instead)

 

I wouldn't suspect it at this point. Try the other suggestions and maybe circle back if still not resolved when all other avenues have been exhausted.

 

Everything you are having problems with uses the MS-CAN bus for communication. It is very comon to have MS-CAN bus issues with water in a taillamp if you have BLIS. Usually fixing the water and the electrical connections to the SOD (Side Object Detection) module fixes al the other issues.

 

I took the taillight out and unplugged it and everything seemed to be back to normal. Went for a 20 minute drive to make sure. All was well until about 15 minutes in and most of the stuff started happening again. It went back to normal once then went off for the rest of the drive, which I extended to 30 minutes.

With the BLIS removed but the taillight plugged in, it's still sending power to that bad BLIS connector, right? I'm wondering what would happen if I disconnect the light assembly altogether. Obviously I wouldn't have a light on the right side, but do you think that would that be a temporary workaround until I can fix it the right way? Not having A/C AND not being able to roll my windows down is killing me in this heat.

 

Did the BLIS connector have corrosion in it? How bad is it? Its not bad enough its fused or bridged pins is it? I would disconnect the BLIS module and leave the taillight assembly connected so you have working lights until the BLIS situation is sorted out. Either clean the connectors really well or find replacement pigtail and replace it.

 

If you disconnect the SOD (BLIS moudule) there will no longer be power going to the module. The problem is, you will still have the interupted MS-CAN (Medium Speed) bus, which currently is not operating properly due to the BLIS issues. You will continue to have problems which every module that uses the MS-CAN bus, and there are a lot, including the FCIM which controls your HVAC.

The taillamp inner connector that connects to the SOD has nothing to due with the taillamps. If you leave that inner connector disconnected, your talliamps should still work. If you entirely disconnect the taillamp on the outside connector, you will have no lights on that side, and the MS-CAN us issue will still be there.

To get your A/C back, you need to either get the original SOD working by fixing the circuit issues and, if necessary, replacing the SOD, which would require programming to work.

There are some possible work-arounds to get your A/C back without fixing the SOD, but they require the ability to reprogram several modules using FORScan or IDS.